In this study, a method to model the semi-infinite extension (unbounded
domain) of the saturated soil is developed. In this method, the unbounded domain is
replaced by an absorbing layer of finite thickness with properties that appreciably
reduce the wave reflection into bounded domain. In this layer, the soil is represented
by the same properties as in the soil close to the foundation (bounded domain) and a
model of frequency-dependent damping is implemented.
A three-dimensional dynamic analysis of rectangular footing on a saturated
soil is carried out. The foundation is subjected to four cycles of harmonic
force. The coupled dynamic equations with u-p formulation based on the
dynamic consolidation theory are used to simulate the soil skeleton and pore
fluid responses. The solid particles of the soil are represented by linear
elastic behavior. It was found that a decay in wave can be noticed when the
unbounded domain of the saturated soil is represented by the energy
absorbing layer. In addition, the maximum displacement of the foundation
will be decreased due to using the energy absorbing layer in comparison with
the elementary boundaries. The excess pore water pressure that developed
during the dynamic loading will be dissipated with time in a fast rate due to
using the energy absorbing layer.